Puffer type circuit breaker

ABSTRACT

A puffer type circuit breaker comprises a contactor device including at least one set of a fixed contactor and a hollow movable contactor provided in a pressure container in which an arc-extinguishing gas of unitary pressure is filed, the contactors being separable relatively from each other, a puffer device for compressing the arc-extinguishing gas in conjunction with a breaking operation, an insulating nozzle formed with an orifice portion surrounding the outer diameter portions of the fixed contactor for driving the arc-extinguishing gas compressed to a high pressure by the puffer device at an arc produced between the contactors, and valve mechanisms provided on the side of the fixed contact and on the side of the movable contactor, respectively, the mechanisms blocking the arc-extinguishing gas until the movable contactor is separated a predetermined distance away from the fixed contactor and thereafter being substantially simultaneously opened. This allows the arc-extinguishing gas to be compressed at pressure permitting the breaking operation and to be blown against the arc in a state where the contactors are separated by a distance permitting the breaking operation with the result of the breaking of a large current.

United States Patent [1 1 Tsubaki et al.

[451 Oct. 1, 1974 PUFFER TYPE CIRCUIT BREAKER [75] Inventors: TohruTsubaki; Minoru Sato; Seizo Nakano, all of Hitachi, Japan [73] Assignee:Hitachi, Ltd., Tokyo, Japan [22] Filed: June 1, 1973 [21] Appl. N0.:366,144

[30] Foreign Application Priority Data June 12, 1972 Japan .Q 47-58815[52] US. Cl. 200/148 A, 200/150 G [51] Int. Cl. H0lh 33/70 [58] Field ofSearch 200/148 A, 150 G [56] References Cited UNITED STATES PATENTS2,78l,435 2/1957 Heilmann et al. 200/150 G 3,527,912 9/1970 Jaillet200/148 A Primary Examiner-Robert S. Macon Attorney, Agent, orFirm-Craig & Antonelli [57] ABSTRACT A puffer type circuit breakercomprises a contactor device including at least one set of a fixedcontactor and a hollow movable contactor provided in a pressurecontainer in which an arc-extinguishing gas of unitary pressure isfiled, the contactors being separable relatively from each other, apuffer device for compressing the arc-extinguishing gas in conjunctionwith a breaking operation, an insulating nozzle formed with an orificeportion surrounding the outer diameter portions of the fixed contactorfor driving the arcextinguishing gas compressed to a high pressure bythe puffer device at an arc produced between the contactors, and valvemechanisms provided on the side of the fixed contact and on the side ofthe movable con tactor, respectively, the mechanisms blocking thearcextinguishing gas until the movable contactor is separated apredetennined distance away from the fixed contactor and thereafterbeing substantially simultaneously opened. This allows thearc-extinguishing gas to be compressed at pressure permitting thebreaking operation and to be blown against the arc in a state where thecontactors are separated by a distance permitting the breaking operationwith the result of the breaking of a large current.

11 Claims, 5 Drawing Figures PAIENIEBIICI nan amazon FIG.

PAIENTED 3.839.613 I SNEEI 0F 4 FIG. 5

1 PUFFER TYPE CIRCUIT BREAKER BACKGROUND OF THE INVENTION 1. Field ofthe Invention The present invention relates to a circuit breaker, andmore particularly to a puffer typecircuit breaker in which anarc-extinguishing gas is compressed in conjunction with a breakingoperation to extinguish an are generated between contactors by blowingthe thus obtained high pressure arc-extinguishinggas against the arc.

2. Description of the Prior Art Recently, with an increasing demand forelectric power transmission lines are carrying greater higher voltagesand higher currents to enable larger capacity power transmission. Acircuit breaker which is utilized as a protective device for such largecapacity transmission lines must be able to cut off a large electriccurrent at a high voltage.

A puffer type circuit breaker is of such a type that anarc-extinguishing gas is compressed in conjunction with a breakingoperation to extinguish an are generated be tween contactors by blowingthe thus obtained high pressure arc-extinguishing gas thereagainst. Forthe arc-extinguishing gas there is used an arc extinguishing insulatingmedium having good extinguishing and insulating properties such as SF(sulfur hexafluoride) gas.

In order to break a high current circuit by means of the puffer typecircuit breaker it is necessary to blow the high pressurearc-extinguishing gas against the arc developed between the contactors.In the abovementioned puffer type circuit breaker, however, difficultyis encountered in obtaining the arc-extinguishing gas at a high pressureat the beginning of the breaking operation because the high pressure ofthe arc-extinguishing gas is generated by compressing thearc-extinguishing gas in conjunction with the breaking operation. Forthis reason, conventional circuit breakers have been constructed in sucha manner that one contactor is permitted to move a predetermineddistance to follow the other contactor at the beginning of the breakingoperation or otherwise have been constructed so as to include a wipestructure adapted to slide one contactor relative to the other over acertain distance, thereby opening the contactors for are generation in astate where an increased breaking speed of the movable contactor andhence an increased pressure at a pressuse generating portion have beenattained subsequent to the initial breaking operation. With thisarrangement, however, the wipe structure could not be made large enough,and in addition, special attention had to be paid to the timing when thehigh pressure arcextinguishing gas is to be blown and to what extent themovable contactor is moved away from the fixed contactor. Thus, a largevolume of arc-extinguishing gas was blown against the contactors at thebeginning of the breaking operation when the pressure of thearcextinguishing gas and the distance between the movable and fixedcontactors were insufficient to extinguish the arc producedtherebetween, thus resulting in a reduced amount of high pressurearc-extinguishing gas available for arc extinguishment. Further, theconventional insulating nozzle for driving the high pressurearc-extinguishing gas generated by a puffer device against the areproduced between contactors could not always efficiently blow the highpressure arcextinguishing gas compressed by the puffer device againstthe arc produced therebetween.

For these reasons, the conventional circuit breakers required a greatamount of high pressure arcextinguishing gas for effecting the breakingof a high current circuit, thus resulting in increased capacity of thepuffer device for compressing the arc-extinguishing gas in order' togenerate the high pressure arcextinguishing gas. In this respect, thedriving of the movable contactor and the puffer device serving as ablowing pressure generator required the large driving force with theresult of the large-sized devices for use in the circuit breakers suchas the external operational device. This brought about the causes of thelarge-sized and complicated circuit breakers. Further, the thusincreased driving force causes an excessive force to be exerted on theoperational rod for mechanically connecting the movable contactor andthe puffer device each held at high potential to the operational deviceheld at earth potential in electrically isolated manner. Thus,difficulty was encountered in manufacturing the insulating operationalrod resistant to such a force.

SUMMARY OF THE INVENTION An object of the present invention is toprovide a puffer type circuit breaker being capable of effecting abreaking operation with high capacity.

Another object of the present invention is to provide a puffer typecircuit breaker having an improved breaking performance wherein anarc-extinguishing gas is held at the beginning of the breaking operationand is then blown against an arc produced between contactors in a statewhere the contactors are separated a predetermined distance.

A further object of the present invention is to provide a puffer typecircuit breaker being capable of effectively extinguishing the arc byimproving the configuration of the insulating nozzle for driving thehigh pressure arc-extinguishing gas to the are produced between thecontactors.

A still another object of the present invention is to provide a puffertype circuit breaker adapted to efficiently blow the high pressurearc-extinguishing gas generated by the puffer device against the areproduced between the contactors by disposing the contactors in theproximity of the puffer device for compressing the arc-extinguishinggas.

Still further objects of the present invention will be understood by wayof embodiments in connection with the accompanying drawings.

A puffer type circuit breaker according to the present inventioncomprises a contactor device including at least one set consisting of afixed contactor and a hollow movable contactor in a pressure containerin which an arc-extinguishing gas of unitary pressure is filled, thecontactors being seperable relatively from each other, a puffer devicefor compressing the arcextinguishing gas in conjunction with a breakingoperation, an insulating nozzle formed with an orifice portionsurrounding outer diameter portions of the fixed contactor for drivingthe arc-extinguishing gas compressed to a high pressure by the pufferdevice at an are produced between the contactors, and valve mechanismsprovided on the side of the fixed contact and on the side of the movablecontactor, respectively, the mechanisms blocking the arc-extinguishinggas until the movable contactor is seperated a predetermined distanceaway from the fixed contactor and thereafter being substantiallysimultaneously opened. This allows the arc-extinguishing gas to becompressed at pressure permitting the breaking operation and to be blownagainst the arc in a state where the contactors are seperated away by adistance permitting the breaking operation with the result of thebreaking of a large current.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross-sectionof a puffer type circuit breaker according to the present invention,showing a closed state.

FIG. 2 is a longitudinal cross-section of the puffer type circuitbreaker of FIG. 1, but showing an opening $1316. 1

FIG. 3 is a longitudinal cross-section of another embodiment of a puffertype circuit breaker according to the present invention, showing aclosed state.

FIG. 4 is a longitudinal cross-section of the puffer type circuitbreaker of FIG. 3, but showing an opening state.

FIG. 5 is a longitudinal cross-section of still another embodiment of apuffer type circuit breaker according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 2 show a puffer typecircuit breaker according to the present invention, its closed state andopening state being shown in FIGS. 1 and 2, respective] In the figuresthere is shown a fixed member 11 on which a main fixed contactor 12 anda fixed arc contactor 13 are mounted. The main fixed contactor 12 isprovided with a plurality of slits 12a thereon except for the upper endportion thereof and with spring means 14 at its tip end portion. Theouter circumferencial portion of the spring means 14 is provided with ashield 15 for limiting an electric field. On the central hollow portionof the fixed arc contactor 13 there is provided a guide rod 16 forguiding the fixed arc contactor 13 therealong and on the tip end portionthereof there is provided a slit 13a adapted to undergo a slightdeformation relative to a force inwardly radially exerted thereon. On amovable portion, on the other hand, there is provided a puffer devicecomprising a puffer cylinder 17 and a puffer piston 18. An insulatingnozzle support on which a base portion of an insulating nozzle 19 ismounted is disposed on the upper surface of the puffer cylinder 17 onthe side of the contactor and secured thereto by means of a bolt 21. Onthe central portion of the insulating nozzle 19 there is formed anorifice portion 190 to define a valve mechanism between the insulatingnozzle 19 and an outer diameter portion of the fixed arc contactor 13.The tip end portion 19b of the insulating nozzle 19 is formed in taperedconfiguration. An inner diameter end portion of the insulating nozzlesupport 20 is provided with a movable arc contactor 22 formed with ahollow construction and the outer diameter end portion thereof isconfigured so as to define a main movable contactor 23. To a pufferchamber 24 defined by the puffer cylinder 17 and the puffer piston 18there is introduced the arcextinguishing gas, which is blown against theare produced between the arc contactors l3 and 22 through an intake port25 provided at the wall of the puffer cylinder 17 on the side of thecontactor. The inner circumferencial surface of the insulating nozzle 19on the side of the puffer cylinder 17 is disposed in the proximity ofthe upper surface of the puffer cylinder 17 with a gap required forintroducing therein the high pressure arc-extinguishing gas. The gap ispreferably configured so as to have substantially the samecross-sectional area as that of the intake port 25. On the centralportion of the puffer cylinder 17 there is provided a puffer cylindershaft 26 having a hollow construction communicating with the hollowportion of the movable arc contactor 22. A plurality of holes 27 areprovided on the side wall of the puffer cylinder shaft 26. A supportcylinder 28 for supporting the puffer piston 18 is disposed surroundingthe puffer cylinder shaft 26 in slidable and gas-tight relation thereto.The support cylinder 28 is provided with a hole 29 for emitting thearcextinguishing gas contained in the puffer cylinder shaft 26 outwardlythrough the hole 27 of the puffer cylinder shaft 26 when the lattermoves a predetermined distance. The support cylinder 28 is fixed to afixed portion.

The puffer cylinder shaft 26 is coupled to an insulating operational rod30 which is, in turn, interlocked with an exteral operational device(not shown). A current collector 31 is provided surrounding the outercircumferential portion of the puffer cylinder 17. These devices aredisposed in a container (not shown) in which the arc-extinguishinginsulating gas of unitary pressure such as SP is filled.

With such an arrangement, a current flows through a path extending fromthe fixed member 11 through the main fixed contactor 12, the mainmovable contactor 23, the insulating nozzle support 20, and the puffercylinder 17 to the current collector 31 in the closed condition as shownin FIG. 1.

In the breaking operation, the insulating operational rod 30and thepuffer cylinder shaft 26 together with the puffer cylinder 17, theinsulating nozzle 19, the main movable contactor 23 and the movable arccontactor 22 are driven downwardly by the external operational device(not shown). This first initiates the separating between the maincontactors 12 and 23. In this state, the current flows though adifferent path extending from the fixed member 11 through the fixed arccontactor 13, the movable arc contactor 22 and the puffer cylinder 17 tothe current collector 31. A further downward movement of the puffercylinder shaft 26 causes the breaking of the arc contactors l3 and 22with the result of the generation of the arc therebetween. On the otherhand, the arc-extinguishing gas contained in the puffer chamber 24defined by the puffer cylinder 17 and the puffer piston 18 is compresseddue to the drive of the puffer cylinder 17. In this state, thearc-extinguishing gas in the puffer chamber 24 remains compressed onlywithin a space formed by the valve mechanism defined by the orifice 19aof the insulating nozzle 19 and the outer diameter portion of the fixedarc contactor l3 and by the valve mechanism defined by the puffercylinder shaft 26 and the support cylinder 28, thus generating nogaseous flow of the arc-extinguishing gas. When the fixed arc contactor13 is further moved and drawn out of the orifice portion 19a of theinsulating nozzle 19 to open the valve mechanism defined by the orificeportion 19a thereof and the outer diameter portion of the fixed arccontactor 13, the hole 27 provided on the puffer cylinder shaft 2ocoincides with the hole 29 provided on the support cylinder 28 of thepuffer piston 18 to effect the simultaneous flow-out of thearc-extinguishing gas compressed to a high pressure through the spacebetween the insulating nozzle 19 and the fixed arc contactor 13 andthrough the hollow portion of the movable arc contactor 22. The highpressure arc-extinguishing gas is blown from the puffer chamber 24against the are 32 to extinguish the latter.

Thus, with the arrangement, no arc-extinguishing gas is blown againstthe arc until it is compressed to a high enough pressure to extinguishthe arc and the fixed arc contactor 13 is seperated away from themovable arc contactor 22 to the extent of permitting the breakingoperation. Consequently, the arc-extinguishing gas is efficientlyutilized for arc extinguishment with the result of breaking a largeamount of current with high efficiency. The efficient blowing of thearc-extinguishing gas permits the volume of the puffer chamber 24 to bemade small and therefore the drive power for the external operationaldevice to be reduced to drive the puffer cylinder 17. In other words,this shows that the use of the conventional external operating devicemakes possible the provision of the breaker having large breakingcapacity.

Further, the inner circumferential surface 19c of the insulating nozzle19 adjacent to the orifice portion 19a thereof and facing the movablearc contactor 22 is formed substantially perpendicular to the breakingdirection between the contactors l3 and 22. This causes the highpressure arc-extinguishing gas to be blown along a directionperpendicular to the breaking direction of the contactors 13 and 22'tothe space where the arc is produced, thus permittinga smoothed blowingoperation against the orifice portion 190 of the insulating nozzle 19and the side of the hollow movable arc contactor 22 with a highlyefficient arc-extinguishing operation. 4

In this case, the main contactors l2 and 23 are disposed outside of theinsulating nozzle 19 for a current flow of large capacity and only thearc contactors 13 and 22 for cutting off the current are disposed withinthe insulating nozzle 19. so that the orificeportion 19a of theinsulating nozzle 19 can be designed to have a cross-sectional areacapable of passing therethrough a predetermined amount ofarc-extinguishing gas necessary for extinguishing the are 32. Thisprevents the arcextinguishing gas from flowing in excess of an amountrequired for arc extinguishment, this ensuring the flow of the requisiteamount of the arc-extinguishing gas without increasing the capacity ofthe puffer chamber 24. The movable arc contactor 22 is disposed in theproximity of the upper surface of the puffer cylinder 17 on the side ofthe contactor with the reduced dead space of the flow path extendingfrom the intake port 25 of the puffer cylinder 17 to the are 32 producedbetween the arc contactors 13 and 22. This allows almost all amounts ofthe high pressure arc-extinguishing gas generated in the puffer chamber24 to be efficiently utilized for extinguishing the are 32 with animprovement in breaking performance.

In the closing operation, the external operational device (not shown)drives the insulating operaional rod 30 upwardly as viewed in thefigure. This causes the up ward drive of the puffer cylinder 17, theinsulating nozzle 19, the main movable contactor 23, and the movable arccontactor 22, so that the fixed arc contactor 13 is inserted to theorifice portion 19a of the insulating nozzle 19 with the first closingof the arc contactors 13 and 22 and then with the closing of the maincontactors 12 and 23. The movement exceeding a certain stroke causes theclosing operation of the valve mechanism defined by the orifice portion19a of the insulating nozzle 119 and the outer diameter portion of thefixed arc contactor 13 and the valve mechanism formed in the hollowportion of the movable arc contactor 22, and thus provides the pufferpiston 18 with a check valve, which is opened at the negative pressureestablished in the puffer chamber 24 to effect the direct introductionof the arc-extinguishing gas from the outside to the puffer chamber 24.

FIGS. 3 and 4 show modified embodiments according to the presentinvention in a closed state shown in FIG. 3 and in opening state shownin FIG. 4. The elements having the same function as those of FIGS. 1 and2 are indicated with the same reference numerals with the detaileddescription omitted for the sake of clarity.

In the figures, a movable contactor is constructed in such a manner thata hollow movable arc contactor 42 is disposed inside of a main movablecontactor 41 with the tip end portion of a fixed contactor 43 formedhollow and interposed between the main movable contac tor 41 and themovable arc contactor 42. The hollow portion of the fixed contactor 43does not communicate with the outside. An arc-proof member is mounted onthe tip end portion of the fixed contacto r 43. At the central portionof the insulating nozzle 19 there is provided an orifice portion 19adefining a valve mechanism between the orifice portion 19a and the outerdiameter portion of the fixed contactor 43. The insulating nozzle 19 isnecessarily made longer by an amount corresponding to an extension ofthe main movable contactor 41 and the movable arc contactor 42 with theresult of the disadyantageously increased dead space by the same amount,but with the simplified construction as compared with that described inconnection with the previous embodiment. The operations of the modifiedembodiment are substantially the same as those of FIGS. 1 and 2. At thebeginning of the operation, the arc-extinguishing gas is enclosed in theinsulating nozzle 19. At the substantially same time when the fixedcontactor 43 is drawn out of the insulating nozzle 19, the hole 28provided on the puffer cylinder shaft 26 of the puffer cylinder 17coincides with the hole 29 provided on the support cylinder 28 of thepuffer piston 18 to form the arc-extinguishing gas as a gaseous flowflowing out through the space between the insulating nozzle 19 and thefixed contactor 43 and through the hollow portion of the movable arccontactor 42 for effecting the blowing of the high pressurearcextinguishing gas against the arc 32. This permits excellentarc-extinguishing with a high current cut off.

FIG. 5 shows a still further embodiment according to the presentinvention wherein a fixed contactor 51 is mounted on the fixed member.The fixed contactor 51 is made of hollow construction with a hole 53provided on the side wall thereof. On the movable portion there isprovided a puffer device comprising a puffer cylinder 54 and a pufferpiston 55. On the upper surface of the puffer cylinder 54 on the side ofthe contactors there is secured an insulating nozzle support 57 formounting an insulating nozzle 56 thereon. The tip end portion 56a of theinsulating nozzle 56 is constructed so as to surround the outer diameterportion of the fixed contactor 51. On the upper surface of the puffercylinder 54 there is fixedly mounted a main movable contactor 58 whichis constituted of a plurality of small pieces arranged in annular formand which is pressed against the outer diameter portion of the fixedcontactor 51 by means of a spring 59. At the inside of the main movablecontactor 58 there is provided a movable arc contactor 60 which is madeof hollow construction and pressed upwardly as viewed in the figure bymeans of spring means 61 and which is adapted to follow the fixedcontactor 51 a certain distance. Surrounding the main movable contactor58 there is provided a cover 62 made of an insulating material forpreventing the main movable contactor 58 and the spring 59 from beingsubjected to damage due to the are produced between the contactors 51and 60.

The arc-extinguishing gas is introduced into a puffer chamber 63 definedby the puffer cylinder 54 and the puffer piston 55. On the wall of thepuffer cylinder 54 on the side of the contactors there is provided anintake port 64 serving as a flow path for blowing the arcextinguishinggas compressed to a high pressure in the puffer chamber 63 against theare produced between the contactors 51 and 60. A puffer cylinder shaft65 has a hollow portion communicating with the hollow portion of themovable arc contactor 60 and has a hole 66 provided at the side wallthereof. A support cylinder 67 for supporting the puffer piston 55 isdisposed surrounding the puffer cylinder shaft 65 and has a hole 68provided for drawing out the arc-extinguishing gas within the puffercylinder shaft 26 when the hole 66 is moved a predetermined distance.The puffer cylinder shaft is coupled to an insulating operational rod69. To the puffer piston there is secured a current collector 70slidable along the inner circumferencial surface of the puffer cylinder.

With this arrangement, a current path is established along a pathextending from the fixed member 11 through the fixed contactor 51, themain movable contactor 58, the puffer cylinder 54, the current collector71 and the puffer piston 55 to the support cylinder 67.

from the main movable contactor 58 as well as to compress the pufferchamber 63. The movable arc contac tor 60 is moved a predetermineddistance following the fixed contactor 51, and thereafter is seperatedfrom the fixed contactor 51 with the result of the generation of thearc. In this state, the arc-extinguishing gas within the puffer chamber63 is only compressed in a space defined by the valve mechanism formedon the sides of the fixed contactor and the movable contactor withoutgenerating the arc-extinguishing gaseous flow. A further drive causesthe hole 53 of the fixed contactor 51 to be drawn out of the tip endportion 56a of the insulating nozzle 56 and the hole 66 of the puffercylinder shaft 26 to coincides with the hole 68 of the support cylinder67 whereupon the arc-extinguishing gas compressed to high pressure flowsout simultaneously through the hollow portion of the fixed contactor 51and that of the movable arc contactor 60 to blow against the are throughthe puffer chamber 24 for are extinguishment. This arrangement permitsthe breaking operation of a large current.

I claim:

1. A puffer type circuit breaker comprising a contactor device includingat least one set of a fixed contactor and a hollow movable contactor ina pressure container in which an arc-extinguishing gas of unitarypressure is filled, said contactors being separable relatively from eachother, a puffer device for compressing said arcextinguishing gas inconjunction with a breaking operation, an insulating nozzle formed withan orifice portion surrounding the outer diameter portion of said fixedcontactor for driving the arc-extinguishing gas compressed to a highpressure by said puffer device at an are produced between saidcontactors, and valve mechanisms provided on the side of said fixedcontactor and on the side of said movable contactor, respectively, saidmechanisms blocking said arc-extinguishing gas until said movablecontactor is separated a predetermined distance away from said fixedcontactor and thereafter being substantially simultaneously opened.

2. A puffer type circuit breaker according to claim 1, wherein saidvalve mechanisms provided on the side of said fixed contactor and on theside of said movable contactor are adapted to open in response to anoperational stroke.

3. A puffer type circuit breaker according to claim 1, wherein saidvalve mechanism provided on the side of said movable contactor comprisesa hole provided at the side wall of a cylindrical operational memberhaving a hollow portion and coupled to a hollow portion of said movablecontactor, and a valve member for blocking said hole at the beginning ofthe breaking operation and for releasing the blocking of said hole aftersaid operational member is moved a predetermined distance.

4. A puffer type circuit breaker according to claim 3, wherein saidvalve member comprises a support member for supporting a fixed portionof said puffer device, said support member having a hollow portionsurrounding said operational member.

5. A puffer type circuit breaker according to claim 1, wherein saidvalve mechanism provided on the side of said fixed contactor is definedby the orifice portion of said insulating nozzle and said fixedcontactor inserted into said orifice portion.

6. A puffer type circuit breaker according to claim 1, wherein saidfixed contactor is formed hollow and said valve mechanism provided onthe side of said fixed contactor is defined by a hole provided at theside wall of said fixed contactor and a portion extending through theorifice portion of said insulating nozzle, said extending portionblocking said hole at the beginning of the breaking operation andreleasing the blocking of said hole after said insulating nozzle ismoved a predetermined distance.

7. A puffer type circuit breaker according to claim 1, wherein the innersurface of said insulating nozzle on the side of said movable contactorand in the proximity of said orifice portion is formed substantiallyperpendicular to a first direction along which said fixed contactor andmovable contactor are oppositely disposed so that said arc-extinguishinggas may be blown from a second direction perpendicular to said firstdirection to a space in which the arc develops.

8. A puffer type circuit breaker according to claim 1, wherein saidfixed contactor comprises a main fixed contactor disposed outside ofsaid insulating nozzle and a fixed arc contactor defining said valvemechanism upon insertion thereof into the orifice portion of saidinsulating nozzle and wherein said movable contactor comprises a mainmovable contactor seperably contacting with said main fixed contactorand a hollow movable arc contactor seperably contacting with said fixedarc contactor.

9. A puffer type circuit breaker according to claim 8, wherein said mainmovable contactor is formed on the outer circumferencial surface of aninsulating nozzle support for fixing said insulating nozzle.

10. A puffer type circuit breaker according to claim 8, wherein saidmovable arc contactor is disposed in the proximity of the upper surfaceof said puffer device and the inner circumferential surface of saidinsulating nozzle on the side of said movable arc contactor is disposedin the upper surface on the side of said movable arc contactor with agap provided therebetween for the flow of the high pressurearc-extinguishing gas.

11. A puffer type circuit breaker according to claim 8, wherein saidfixed arc contactor is adapted to be inserted to the hollow portion ofsaid hollow movable arc contactor and said fixed arc contactor isprovided with means for applying a pressure contact to said movable

1. A puffer type circuit breaker comprising a contactor device including at least one set of a fixed contactor and a hollow movable contactor in a pressure container in which an arcextinguishing gas of unitary pressure is filled, said contactors being separable relatively from each other, a puffer device for compressing said arc-extinguishing gas in conjunction with a breaking operation, an insulating nozzle formed with an orifice portion surrounding the outer diameter portion of said fixed contactor for driving the arc-extinguishing gas compressed to a high pressure by said puffer device at an arc produced between said contactors, and valve mechanisms provided on the side of said fixed contactor and on the side of said movable contactor, respectively, said mechanisms blocking said arc-extinguishing gas until said movable contactor is separated a predetermined distance away from said fixed contactor and thereafter being substantially simultaneously opened.
 2. A puffer type circuit breaker according to claim 1, wherein said valve mechanisms provided on the side of said fixed contactor and on the side of said movable contactor are adapted to open in response to an operational stroke.
 3. A puffer type circuit breaker according to claim 1, wherein said valve mechanism provided on the side of said movable contactor comprises a hole provided at the side wall of a cylindrical operational member having a hollow portion and coupled to a hollow portion of said movable contactor, and a valve member for blocking said hole at the beginning of the breaking operation and for releasing the blocking of said hole after said operational member is moved a predetermined distance.
 4. A puffer type circuit breaker according to claim 3, wherein said valve member comprises a support member for supporting a fixed portion of said puffer device, said support member having a hollow portion surrounding said operational member.
 5. A puffer type circuit breaker according to claim 1, wherein said valve mechanism provided on the side of said fixed contactor is defined by the orifice portion of said insulating nozzle and said fixed contactor inserted into said orifice portion.
 6. A puffer type circuit breaker according to claim 1, wherein said fixed contactor is formed hollow and said valve mechanism provided on the side of said fixed contactor is defined by a hole provided at the side wall of said fixed contactor and a portion extending through the orifice portion of said insulating nozzle, said extending portion blocking said hole at the beginning of the breaking operation and releasing the blocking of said hole after said insulating nozzle is moved a predetermined distance.
 7. A puffer type circuit breaker according to claim 1, wherein the inner surface of said insulating nozzle on the side of said movable contactor and in the proximity of said orifice portion is formed substantially perpendicular to a first direction along which said fixed contactor and movable contactor are oppositely disposed so that said arc-extinguishing gas may be blown from a second direction perpendicular to said first direction to a space in which the arc develops.
 8. A puffer type circuit breaker according to claim 1, wherein said fixed contactor comprises a main fixed contactor disposed outside of said insulating nozzle and a fixed arc contactor defining said valve mechanism upon insertion thereof into the orifice portion of said insulating nozzle and wherein said movable contactor comprises a main movable contactor seperably contacting with said main fixed contactor and a hollow movable arc contactor seperably contacting with said fixed arc contactor.
 9. A puffer type circuit breaker according to claim 8, wherein said main movable contactor is formed on the outer circumferencial surface of an insulating nozzle support for fixing said insulating nozzle.
 10. A puffer type circuit breaker according to claim 8, wherein said movable arc contactor is disposed in the proximity of the upper surface of said puffer device and the inner circumferential surface of said insulating nozzle on the side of said movable arc contactor is disposed in the upper surface on the side of said movable arc contactor with a gap provided therebetween for the flow of the high pressure arc-extinguishing gas.
 11. A puffer type circuit breaker according to claim 8, wherein said fixed arc contactor is adapted to be inserted to the hollow portion of said hollow movable arc contactor and said fixed arc contactor is provided with means for applying a pressure contact to said movable arc contactor. 